Mold for cementitious material



July 7, 1942. o. s. BURMAN MOLD FOR CEMENTITIOU S MATERIAL Filed Nov.18, 1940 2 Sheets-Sheet l nvenior' 0107 151' Barman By fiMAfforneyJ M WMJuly 7, 1942. o. s. BURMAN 2,288,991

MOLD FOR CEMENTITIOUS MATERIAL Filed Nov. 18, 1940 2 Sheets-Sheet 2 2/ wI Jnvniar Z0 Olaf v31 Barman By lil'dflborneya 'l' l .".'IIIIE"IIIIIIIIIII// Patented July 7, 1942 UNITED STATES PATENT OFFICE MOLD FORCEMENTITIOUS MATERIAL Olof S. Burman, Minneapolis, Minn.

Application November 18, 1940, Serial No. 368,101

6 Claims.

My present invention provides a highly efficient mold for the casting ofcementitious materials and, generally stated, consists of the noveldevices, combinations of devices, and arrangement of parts hereinafterdescribed and defined in the claims.

Particularly the invention is directed to the provision of a mold forcasting concrete or cementitious laundry tubs with either single ormultiple compartments, as desired. Hitherto molds for casting of suchcementitiou tubs have involved an outer shell and an inner shell or corearranged to be properly spaced for the pouring of the fluid concrete orcementitio-us material; but such molds have not been well adapted forthe casting or molding of tubs having in wardl projecting shelves.

My invention relates particularly to the structure of the inner shell orcore and provides improvements in the inner shell or core, whereby thecasting of the tub with inwardly projecting shelf is made an easy matterand in which scams or joints in the visible interior of the tub will beeliminated. This improved feature involves a ledge plate hingedlyconnected to the main body of the inner shell or core but which, whenturned to an inoperative position, will permit the inner shell or coreto be readily removed from the interior of the cast tub.

The above ledge-forming plate is preferably made somewhat shorter thanthe width of the tub compartment and for an important reason, which willhereinafter more fully appear, the core is formed with openings at theends of the ledge plate and these openings are arranged to be closed bycorner plates to complete the core for molding action.

A commercial form of the improved mold is illustrated in theaccompanying drawings wherein like characters indicate like partsthroughout the several views.

Referring to the drawings:

Fig. 1 is a view in perspective, but with some parts sectioned, showingthe elements of the improved mold turned upside down for the purpose ofmolding the tub which latter is also indicated in Fig. 1;

Fig. 2 is a view in perspective showing the inner shell or core removedfrom working position and turned right side up;

Fig. 3 is a fragmentary section taken on the line 33 of Fig. 2;

Fig. 4 is a fragmentary view in plan showing in detail certain partsfound in the immediate vicinity of one side of Fig. 2;

Fig. 5 is a section taken through the inner shell or core on the line 55of Fig. 2 and showing in section also the molded or cast tub from whichthe outer shell has been removed;

Fig. 6 is a view corresponding to Fig. 5 but showing by dotted lines theadjustments of the elements of the inner shell for removal from the castor molded tub; and

Fig. 7 is a detail in horizontal section taken on the line 'l'! of Fig.2.

The cast or molded tub is indicated by the numeral [0 and is formed withan integral inwardly projecting shelf H. The tub here illustrated is ofthe general character disclosed and claimed in my Design Patent No.117,329 of October 24, 1939.

My improved mold is especially adapted for the molding of tubs of theabove character, to wit: tubs with inwardly projecting shelves such asare frequently designated as soap trays.

The outer shell of the mold is made up of side plates I2 connected attheir ends by end plates l3, the outer shell thus formed being normallyopened at bottom and top. In practice, it has been customary to rigidlybut detachably connectthe plates I2 and I3 at their abutting edges. Thisouter shell is arranged to rest upon the bars M of a rectangular baseframe, shown as made up of angle irons. The bars M are shown with raisedaligning ribs or ledges It which properly locate the outer shell when itis seated on the base frame in an inverted position, as shown in Fig. 1.In Fig. 1 the side plates l2 are shown as reinforced by angle bars orribs it.

The inner shell or core H is made of such form that it will be spacedfrom but it will be parallel to the plates of the outer shell, therebyleaving the proper space for the casting of the tub. The normal bottomof this inner shell I! is closed, but when the inner shell is inverted,as shown in Fig. 1 and placed upon the frame [4, its downturned edgeswill be just inward of the aligning ribs l5 and the two shells will beproperly spaced for the molding of the tub.

To form the top of the shelf II the inner shell is formed with a rigidinwardly projecting plate I8 which, as shown. is additionally supportedand made rigid with the inner shell by bars l9. As best shown in Fig. 2,the normal top of the inner shell H has edge flanges inturned at I1 andwhich flanges, when the inner shell and core is inverted as shown inFig. 1, rest directly on the bars 14. Just below the plate |8 the backof shell or core I! is cut away at to form a space for the hinged ledgeplate 2| and for end blocks or pieces 22. The ledge plate 2| is hingedlyconnected at 23 to the rear wall of the inner shell or core IT. The endblocks 22 fit in the ends of the recess 20 and are flanged to correspondto the cross-section of the ledge plate 2|, to the ends of which theyare arranged to be aligned. The hinged ledge plate 2|, at its free edge,see Fig. 5, is arranged to be aligned with the downturned edge flange l8of the fixed plate |8, thereby properly spacing the said elements l8 and2| for forming the shelf I.

As a simple means for locking the ledge plate 2|, in the position juststated and as shown in Fig. 5, a lock-bolt 24 is shown as pivotallyconnected thereto and provided with a nut 25. When nut 25 is loosened,bolt 24 is arranged to be turned into a notch 26 of a metal strap 21which is shown as rigidly secured to and projects from the fixed platel8.

To detachably but securely hold the end blocks or plates 22 in workingpositions, they are shown as provided with pivotally connected levers 28that are adapted to be turned against the end walls of the inner shelland under spring-acting retaining flanges 29 secured on the interior ofthe end plates of the said inner shell.

The use of the improved mold is probably obvious from the foregoingstatements, but may be briefly summarized as follows:

Inner and outer shells are applied on the base frame M, as alreadydescribed, with the end blocks and the ledge plate locked in theoperative positions stated, and then the concrete or cementitiousmaterial is poured into the mold through the open top of the outer shelland against the inverted bottom of the inner shell. When the interior ofthe mold has been properly filled, the bottom of the tub, which is theninverted, will be levelled off and the tub allowed to set in itsinverted position until it is properly set or hardened; then the outershell will be first removed; next, the formed tub with the inner shellapplied will be turned right side up and the inner shell will be removedfrom the tub. As clearly shown in Fig. 6 by dotted lines, the removal ofthe inner shell or core is made an easy matter when the end blocks orplates 22 have first been removed and then the ledge plate 2| is turnedfirst downward to the position indicated by full lines in Fig. 6,thereby permitting the inner shell or core to be removed, as indicatedby dotted lines in said view.

In the forming of multi-compartment tubs, two or more of the innershells or core-forming elements will be placed within the outer shell,spaced apart properly for the forming of the tub partitions. Of coursethe outer shell will be made in a length proper for forming tubs of thedesired number of compartments. The most common form of the tub will, ofcourse, be a two-compartment tub which would require two of the abovedescribed inner shells or cores.

The outer surfaces of the corner blocks 22 are flush with the end platesof the core and with the ends of the ledge plate 2| and fit the samewith close joints so that there will be very little seam line formed onthe interior of the tub; and, moreover, even these slight seam or jointlines are entirely under the shell H, and hence, will not be within theline of vision of a person using or inspecting the tub. Seam or jointlines on the interior of the tub, where in full View, are veryobjectionable and all such are avoided in the use of my improved mold.

In actual practice this improved tub has been found to be highlyefficient and to very greatly reduce the amount of labor required informing laundry tubs of the character referred to. It will, of course,be understood that a preferred form of the mold above described iscapable of various modifications Within the scope of the inventionherein disclosed and broadly claimed.

What I claim is:

1. In a tub molding device, an inner coreforming shell having inwardlyprojecting upper and lower shelf-forming plates extended along one wallof said shell, said lower plate being displaceable to permit removal ofsaid shell after the molded tub with inwardly projecting shelf has setand hardened.

2. In a tub molding device, an inner coreforming shell having inwardlyprojecting upper and lower shelf-forming plates extended along one wallof said shell, said upper plate being relatively fixed to said shell andsaid lower plate being displaceable to permit removal of said shellafter the molded tub with inwardly projecting shelf has set andhardened, said lower plate being made in sections and including anintermediate portion and corner-forming end blocks having independentsecuring means.

3. The structure defined in claim 1 in which said displaceable lowershelf-forming plate is hingedly connected to the back of said innershell and is provided, at its free edge, with means for detachablylocking the same to said upper shelf-forming plate.

4. The structure defined in claim 1 in which said displaceable lowershelf-forming plate is hingedly connected to the back of said innershell and is provided, at its free edge, with means for detachablylocking the same to said upper shelfforming plate, and in furthercombination with corner blocks set into the side Walls of said innershell at the ends of said displaceable lower shelfforming plate.

5. The structure defined in claim 2 in which said upper shelf-formingplate is provided with a projecting notched lug and said displaceablelower shelf-forming plate is provided with a nut-equipped boltengageable with said notched lug to lock said two shelf-forming platesin cooperative shelf-forming position,

6. The structure defined in claim 1 in which said displaceable lowershelf-forming plate is hingedly connected to the back of said innershell and is provided, at its free edge, with means for detachablylocking the same to said upper shelf-forming plate, and in furthercombination with corner blocks set into the side walls of said innershell at the ends of said displaceable lower shelf-forming plate, saidcorner blocks having projecting lock levers pivoted thereto and thesides of said inner shell having retaining clips with which said leversare fric tionally engageable to detachably hold said corner blocks inoperative positions.

I OLOF S. BURMAN.

